Abstract

This study investigates the effects of human visitation on Australian sea lions (Neophoca cinerea) hauled out at Carnac Island Nature Reserve, near Perth, Western Australia. Male sea lions haul out on Carnac Island's main beach year round, and this is also where recreational boaters and tourists land when visiting from the mainland, thus coming into close contact with the sea lions. There was no significant difference in the rate of return of sea lions to the beach between low-moderate and high human visitation seasons. However, there was a specific profile of sea lion response to human approaches; the level of sea lions' vigilance was mainly a function of age (higher in juveniles than in adults) and time of the day (higher in the early part of the day). Remarkably, vigilance levels did not change with the distance of approach of humans to sea lions nor with the number of humans involved. With regard to spatial competition between sea lions and people on the beach, the section of beach where most people landed was the least often used by sea lions. This last result, however, was inconclusive, as habitat preference could have been involved in where sea lions chose to haul out. Finally, repeated incidental observations were made of direct interference of sea lions by humans, including approaches at very close range of less than 2.5 m, and throwing water and sand at sea lions. Suggested visitor management actions to reduce potential impacts of human presence on sea lions included: limiting the overall numbers of visitors to Carnac Island's main beach at peak visitation times, implementing a visitor interpretation and education program, and establishing a stronger ranger presence at the site.